This research aims to discuss: (1) How is ta'zir implemented at the Fadliliah Tambak Sumur Waru Islamic Boarding School, Sidoarjo?; (2) How does ta'zir at the Fadlillah Tambak Sumur Waru Islamic Boarding School, Sidoarjo, apply discipline to students? This research uses a descriptive qualitative approach. Data collection techniques use interviews, participant observation and documentation. Data analysis consists of data reduction, data presentation and drawing conclusions. Checking the validity of the data is carried out through extended participation, diligent or consistent observation, triangulation and peer checking. The results of this research explain that (1) the Fadlillah Waru Sidoarjo Islamic Boarding School provides disciplinary guidance to students in order to achieve educational goals in the Islamic boarding school environment. This disciplinary action takes the form of giving punishment (ta'zir), for example going bald, destroying the Koran and so on. Disciplinary action against students at the Fadlillah Waru Sidoarjo Islamic boarding school is a way of disciplining boarding school administrators towards problematic students so that they obey the rules that have been set and agreed upon by the management of the boarding school. The application of punishment is also understood as a means of educating students so that it has a deterrent effect and does not repeat it again; (2) Ta'zir is considered an effective method in the process of disciplining students. However, this does not necessarily become the main step in the disciplinary action. Sometimes these actions actually make students feel depressed.Penelitian ini bertujuan untuk membahas: (1) Bagaimana penerapan ta‘zir di Pondok Pesantren Fadliliah Tambak Sumur Waru Sidoarjo?; (2) Bagaimana ta‘zir di Pondok Pesantren Fadlillah Tambak Sumur Waru Sidoarjo dalam menerapkan kedisiplinan pada santri? Penelitian ini menggunakan pendekatan kualitatif deskriptif. Teknik pengumpulan data menggunakan wawancara, observasi partisipan dan dokumentasi. Analisis data terdiri dari reduksi data, penyajian data dan penarikan kesimpulan. Pengecekan keabsahan data dilakukan melalui perpanjangan keikutsertaan, ketekunan atau keajegan pengamatan, triangulasi dan pemeriksaan teman sejawat. Hasil penelitian ini menjelaskan bahwa (1) Pondok Pesantren Fadlillah Waru Sidoarjo melakukan pembinaan pendisiplinan kepada santri guna tercapainya tujuan pendidikan di lingkungan pesantren. Tindakan pendisiplinan tersebut berupa pemberian hukuman (ta‘zir), misalnya gundul, menghatamkan Al-Qur’an dan lain sebagainya. Tindakan pendisiplinan kepada santri di pondok pesantren fadlillah waru sidoarjo merupakan cara dalam pendisiplinan pengurus pondok terhadap santri yang bermasalah agar taat kepada peraturan-peraturan yang telah ditetapkan dan disepakati oleh pihak pengelola pengurus pondok pesantren. Penerapan hukuman juga dipahami sebagai sarana dalam mendidik santri agar menimbulkan efek jera dan tidak mengulanginya kembali; (2) Ta‘zir diangggap metode yang efektif dalam proses pendisiplinan santri. Namun, hal itu tidak lantas dijadikan langkah utama dalam tindakan pendisiplinan tersebut. Terkadang tindakan tersebut justru menjadikan santri menjadi tertekan
